Color oscillograph recording paper



United States Patent 3,499,758 COLOR OSCILLOGRAPH RECORDING PAPER CarlE. Johnson and Dewey M. Dumers, Binghamton, N.Y., assignors to GAFCorporation, New York, N.Y., a corporation of Delaware No Drawing. FiledJune 7, 1965, Ser. No. 462,063

Int. Cl. G03c 7/18 US. Cl. 9622 11 Claims ABSTRACT OF THE DISCLOSUREMulticolor recording paper for recording oscillograph traces in at leastthree colors comprising, on the flexible support, a hardened silverchlorobromide emulsion, sensitized to green light and containing amagenta color former, a hardened gelatin interlayer, a hardened silvebromoiodide emulsion having high blue sensitivity and containing acyancolor former, and an outer hardened gelatin surface layer.

This invention relates to color oscillograph recording materials and,more particularly, to photosensitive recording paper having utility forrecording oscillograph traces in at least three colors.

Photosensitive papers adapted for light recording, for example,oscillograph, recordings, are known. Such materials are both of theprint-out type and the developingout type. The print-out type ofmaterial requires no development step and may or may not be fixed. Suchmaterials are generally much slower than the materials used indeveloping-out processes and have poor image permanency. Thedeveloping-out type, as the name implies, requires that the exposedmaterial be chemically developed, fixed and washed in order to provide astable visible image on said material. It is this second type ofprinting material with which the present invention is concerned.

As light recording, e.g., oscillograph recording, has increased inimportance, there have evolved fields of use in which a multi-coloredrecording is desirable. Wind tunnel and flight testing are examples ofprocedures where a plurality of colored traces is of considerable value.Idealized trace separation and readout of recorded data, of course,improves efficiency of inspection in changing conditions of operationand hence, is desired. Further, test results which can be recorded andvisually observed in a relatively brief interval of time and using asimplified system of processing with a minimum number of solutions isalso desired.

An object of this invention, therefore, is to provide a new recordingmaterial for use in oscillograph recording which will improve traceseparation and readout. Another object of this invention is to provide asimplified system of processing such papers for development employing aminimum number of solutions. Another object of this invention is toprovide a color system which closely approximates the handlingprocedures used with conventional black and white oscillograph papers.Still another object is a procedure which does not require a bleach stepto remove image silver as required in conventional color systems. Otherobjects, as well as advantages emanating from this invention will becomeapparent from a reading of the following description.

The above objects are accomplished in accordance with the presentinvention which contemplates a photographic material comprising aflexible support bearing on at least one surface thereof (a) anundercoat comprising a silver chlorobromide emulsion layer having a lowblue sensitivity, being practically insensitive to light having a wavelength of 460 microns and above before optical sensitization, beingsensitized to the green region of the spectrum ice and containing acolorless color former fast to diffusion capable of reacting with theoxidation products of an aromatic p-amino-developing agent to form amagenta dye image; (b) a separating layer comprising a hardened gelatinlayer; (c) an outer coating comprising a silver bromoiodide emulsionlayer having a high sensitivity to the blue light without containing anoptical sensitizing dye, but containing a color former capable offorming a cyan dye image upon color development; and (d) a hardenedgelatin surface layer.

The terms photographic paper and recording paper are used throughout thespecification and claims to include photosensitive emulsions disposed inany suitable support such as paper, film or other usable medium. It ispreferred, however, to employ a paper such as 45-90 grams/ square meterDocument Paper rag) without baryta coat or other surface or a papersimilar thereto.

Briefly, the invention contemplates conventional photographic recordingtechniques in exposing the photosensitive emulsions to light in anoscillograph recorder. The recorder is necessarily provided withsuitable colored filters in front of galvanometers used in conjunctiontherewith. The conventional photographic recording techniques, generallyreferred to as oscillography, involves the exposure of an entire roll ofa record paper to the information to be recorded with subsequent andseparate chemical development of the roll thus exposed. In thisprocedure a record roll of approximately 250400 feet in length isentirely exposed before its removal from the oscillographic recorder andits subsequent development by conventional means.

In accordance with the invention, the color formers employed herein arethose which are well known in the photographic art. The term colorformer is use throughout the specification and claims to define anessentially colorless compound fast to diffusion which is capable ofreacting with the oxidation products of an aromatic p-amino developingagent, particularly of the N,N-disubstituted p-phenylenediamine seriesas exemplified by N,N- diethylamino aniline, N,N-di (Bhydroxyethyl)-aniline and the like, to produce dyes of the azomethine,quinoneimine, indoaniline and phenazine (azine) series. Such colorformers are well known to persons skilled in the art and described inthe patent literature, for instance in United States Patents 2,500,487;2,547,307; 2,829,975 and others. Illustrative of the color formers whichare usable in accordance with this invention are compounds such as:1-octadecyl-2-(2',1-hydroxynaphthyl) benzimid azole-S- sulfonic acid asa cyan color former; 1-(4-phenoxy-3'- sulphophenyl)-3-stearyl-5-pyrazoleas a magenta color former; and2-(4-benzolylacetaminophenyl)-l-octadecylbenzimidazole-S-sulfonic acidas a yellow color former. Generally speaking the quantity of colorformer used per unit of silver halide is selected in such a. way thatsufficient density of the trace is achieved upon exposure and developingso as to provide proper readout. Specifically, it is recommended thatthe ratio of color former to silver halide per silver halide emulsionlayer be about 10 millimols of color former to about 2 to 20 grams ofsilve halide.

The invention contemplates the use of a sensitizing dye capable ofsensitizing in the green region of the spectrum. If desired, the bluesensitivity of the blue sensitive layer can be further increase-d by theuse of a sensitizing dye for the blue. It is preferred that these dyesThe emulsions may contain the usual coating finals such as thoseproposed to retard or prevent fog in light-sensitive silver halideemulsions. These compounds are commonly referred to as antifoggants orstabilizers and are, in many instances, heterocyclic compounds with aplurality of nitrogen atoms or with a mercapto group in their molecule.

Certain other adjuvants normally incorporated into silver halidephotographic emulsions, such as wetting agents, may also be employed.

In accordance with this invention, it is contemplated to treat theaqueous gelatin dispersions and gelatin silver halide emulsions employedherein with a hardening agent in order to reduce the tendency of thelayers to soften, melt or reticulate during processing, particularly attemperatures which are higher than the temperature of 68 F. (20 C.)previously specified for the processing of photographic materials.Compounds which have been used for the hardening of gelatin and gelatinemulsion layers include formaldehyde, hydroxyaldehydes, glyoxal and itsderivatives, triacrylformal, as well as mixtures of such aliphaticaldehydes with an aromatic hydroxy compound such as phenol, orresorcylic aldehyde. Other con ventional hardeners also applicableinclude alum, chromalum, chromium acetate and the like.

Suitable supports for the novel silver halide emulsions and elements ofthis invention include the flexible supports used in the prior art foroscillographic recordings. These supports may be transparent but, ingeneral, a photographic grade flexible paper is selected. In thisregard, 55 g./m. of Document Paper (100% rag) without a baryta coatingor other surface coating is especially preferred. However, there can beused any other flexible material suitable for coating with aphotographic colloid silver halide emulsion.

The invention will be further illustrated by, but is not limited to, thefollowing examples:

EXAMPLE I An improved recording paper was prepared by adding to 1000grams of a low blue sensitive chlorobromide emulsion the followingingredients: 120 cc. of a 1:2000 solution containing a sensitizing dyefor the green; 0.5 gram of an antifoggant; 30 cc. of a solution of anammonium salt of a sulfate ester of an alkyl phenoxypolyoxyethyleneethanol which serves as a coating aid; 1.2 grams of a triacrylformalhardener; and grams of a magenta color former having the formula:

500 cc. of water was added to the above emulsions so as to adjust it forthe proper coating viscosity on 55 gram Document Paper (100% rag). Thiscoating was applied to a thickness corresponding to a metallic silvercoating weight of 0.4 to 0.5 gram per square meter.

In the same operation but at a different coating station, a 3.5 percentby weight gelatin surface solution containing the above wetting agentand 18 cc./kg. of a 10 percent formaldehyde solution was added.

In a second coating operation to 1000 grams of a high speed bromoiodideemulsion was added 0.5 gram of an antifoggant; cc. of a 10 percentsolution of an ammonium salt of a sulfate ester of an alkylphenoxypolyoxyethylene ethanol which serves as a coating aid; 1.2

ill

grams of a triacrylformal hardener; and 15 grams of a cyan color formerhaving the formula:

1000 cc. of water was added to the above emulsion so as to adjust it fora proper coating viscosity. The soadjusted emulsion was coated on top ofthe magenta layer to a coating thickness corresponding to a metallicsilver coating weight of about 0.7 to 0.8 gram of silver per squaremeter.

In the same operation, but at a different coating station, 3.5 percentby Weight of the above-described gelatin solution was applied.

The material with the two silver halide layers was exposed using acommercially available oscillograph (manufactured by the MidwesternInstruments Corp.) employing a tungsten light source under the followingconditions:

The lamp voltage was set at 12 volts and paper travel rate was adjustedat 2.5 inches/ second.

In order to expose the recording paper, signal generators were used toapply a sine wave of 20 cycles/second to each galvanometer and theamplitude was varied to give a trace deflection of from 1 to 4 inches.

The resulting exposed material was then placed in a standard automaticoscillogram processor as manufactured by Consolidated ElectrodynamicsCorp. and processed at a rate of about 4 feet/minute. In such processorapparatus 4 tanks were utilized, each being maintained at a temperatureof about F., with the following tank arrangement as to contents:

Tank No.: Tank contents 1 Color developer. 2 Do. 3 Fixer.

The availability of two developer and two fixer tanks made it possibleto extend the processing time and to extend the useful life of theprocessing solution.

In the foregoing the color developer and fixer utilized contained thefollowing ingredients and in the following amounts:

Color developer Ingredient: Amount, grams Sodium pyrophosphate 1.0Sodium sulfite (anhydrous) 4.0

Sodium carbonate (monohydrate) 60.0 Potassium bromide 1.04-N,N-di(fi-hydroxyethyl)-aminoaniline 7.5 Water up to 1 liter with pHadjusted to 10.6.

Fixer Ingredient: Amount, grams HYPO (sodium thiosulfate, anhydrous-130.0 Water up to 1 liter.

The resulting processed paper showed four distinct and separate traces,namely, cyan, magenta, deep blue and purple. The magenta trace wasproduced by the light from galvanometer A which was fitted with theyellow filter. The cyan trace was produced by the light fromgalvanometer B which was fitted with the magenta filter. The deep bluetrace was produced by the light from galvanometer C which was fittedwith the pale magenta color-correction filter and the purple trace bythe light from galvanometer D, which was not fitted with a filter.

It should be noted that in practice the filters selected to produce thevarious desired colored trace lines are determined by the speed of thesensitive material as related to the light source intensity and thecolor temperature. Thus, the above filters were selected for use with atungsten light source. For practical use with an oscillograph using a UVlight source, other filters may be needed especially to balance theso-called white light trace. Nonlimiting examples of the filters whichmay be suitably employed are as follows:

Color trace: Filter type Magenta Wratten Nos. 12, 15, 16, 56, 57, 8, 61,74. Cyan Wratten Nos. 32, 34, 47B, 48, 49. Blue to bluish magentaNeutral density or pale magenta color correction or pale yellow colorcorrection filters.

EXAMPLE 2 A recording paper was prepared in a manner similar to that ofExample 1 exceptfor changes in the color formers employed. Thus, thepaper was prepared by adding to 1000 grams of a low blue sensitivechlorobromide emulsion the following ingredients: 120 cc. of asensitizing dye for the green, 0.5 gram of an antifoggant; 30 cc. of asolution of the ammonium salt of a sulfate ester of an alkylphenoxypolyoxyethylene ethanol which serves as a wetting agent; 1.2grams of triacrylformal hardener; and 10 grams of the magenta colorformer employed in Example 1, and 5 grams of a yellow color formerhaving the formula:

About 500 cc. of water was added to adjust the emulsion to the properviscosity for coating on 55 gram Document Paper to a coating weightcorresponding to about 0.4 to 0.5 gram of silver/square meter.

In the same operation, a 3.5 percent by weight gelatin surface solutioncontaining a wetting agent and 18 cc./kg. of a 10% formaldehyde solutionwas added to form a surface coating.

In a second operation, a layer was coated prepared from a high-speedbromoiodide emulsion containing 0.5 gram of an antifoggant; 30 cc. ofthe above wetting agent solution; 1.2 grams of a formaldehyde hardenerand 10 grams of the cyan color former employed in Example 1 and 5 gramsof the yellow color former employed in Example 1.

Similar to the procedure of Example 1, a 3.5% by weight solution ofgelatin and formaldehyde hardener was applied as a surface coating.

The resulting recording paper was exposed and processed in the apparatusemployed in Example 1 with the following results being obtained:

The light from galvanometer A which was filtered with the yellow filterproduced a red trace; the light from galvanometer B fitted with themagenta filter produced a green trace. Unfiltered light was found toproduce a substantially neutral gray trace.

The processing technique employed offers several advantages. Theavailability of two developer and fixer tanks makes it possible toextend not only the developing time and fixing time but also the usefullife of the processing solutions. The omission of the bleaching stepresults in color pictures which contain a warm tone silver deposit.

The presence of the silver deposit makes it possible to reproduce theoscillograph recording on diazotype materials.

Modifications of the invention will occur to persons skilled in the art.It is, therefore, not intended to be limited in the patent grantedexcept as necessitated by the appended claims.

What is claimed is:

1. A multicolor recording paper for recording oscillograph traces in atleast three colors which comprises a flexible support bearing on atleast one surface thereof in the following order: (a) a hardened silverchlorobromide emulsion substantially insensitive to light of a wavelength of 460 microns and above, being optically sensitized to the greenand containing a color former capable of forming a magenta dye imageupon color development, (b) a hardened gelatin intersurface layer, (c) ahardened silver bromoiodide emulsion coating having blue sensitivity andcontaining a color former capable of forming a cyan dye image upon colordevelopment, and (d) as an outer surface layer a hardened gelatin layer,each of said emulsion layers being coated to a silver coating weight of0.4 to 0.8 gram silver per square meter.

2. A recording paper according to claim 1 wherein the lower silverchlorobromide emulsion layer contains a mixture of a magenta and ayellow color former.

3. The paper of claim 1 in which the upper silver bromoiodide emulsionlayer contains a color former for the cyan image and a color former forthe yellow image.

4. The paper of claim 1 in which the lower silver emulsion layer iscoated to a silver coating weight of from about 0.4 to 0.5 gram silverper square meter, and the outer emulsion layer is coated to a silvercoating weight of from about 0.7 to 0.8 gram silver per square meter.

5. The paper of claim 1 in which the silver halide emulsion layer ishardened with triacrylformal.

6. The paper of claim 1 in which the magenta color former has theformula:

7. The paper of claim 1 in which the: cyan color former has the formula:

| I? I H31 CN- COOH COOH 8. The paper of claim 1 in which both the lowersilver chlorobromide and the upper bromoiodide emulsion layers contain ayellow color former having the formula:

9. The paper of claim 6 in which said magenta color former is mixed witha yellow color former.

10. The paper of claim 7 in which said cyan color former is mixed with ayellow color former.

11. The process of forming a multicolored image which comprises exposingwith a plurality of selectively filtered colored lights, a multicolorrecording paper for recording oscillograph traces in at least threecolors which comprises a flexible support bearing on at least onesurface thereof in the following order: (a) a hardened silverchlorobromide emulsion substantially insensitive to light of a wavelength of 460 microns and above, being optically sensitized to the greenand containing a color former capable of forming a magenta dye imageupon color development, (b) a hardened gelatin intersurface layer, (c) ahardened silver bromoiodide emulsion coating having blue sensitivity andcontaining a color former capable of forming a cyan dye image upon colordevelopment, and (d) as an outer surface layer a hardened gelatin layer,each of said emulsion layers being coated to a silver coating Weight of0.4 to 0.8 gram silver per square meter, developing the imagewiseexposed recording material with a developer solution comprising anaromatic amino developing agent and fixing the color developed materialWithout bleaching the processed material.

References Cited UNITED STATES PATENTS 3,226,234 12/1965 Himmelman eta1. 96-111 3,265,503 8/1966 Bodmer et a1. 96-74 3,372,030 3/1968Jacobson 9660 OTHER REFERENCES NORMAN G. TORCHIN, Primary Examiner M. F.KELLEY, Assistant Examiner US. Cl. X.R. 9674 Disclaimer 3,499,758.CarlE. Johnson and Dewey M Dumers, Binghamton, N.Y. COLOR OSCILLOGRAPHRECORDING PAPER. Patent dated Mar. 10, 1970. Disclaimer filed Sept. 30,1982, by the assignee, Eastman Kodak Co.

Hereby enters this disclaimer to all claims of said patent. [OflicialGazette March 22, 1983.]

